1. Field
The disclosed embodiments relate to batteries for portable electronic devices. More specifically, the disclosed embodiments relate to mechanical supports that improve the resistance of battery cells in portable electronic devices to mechanical stress.
2. Related Art
Rechargeable batteries are presently used to provide power to a wide variety of portable electronic devices, including laptop computers, tablet computers, mobile phones, personal digital assistants (PDAs), digital music players and cordless power tools. The most commonly used type of rechargeable battery is a lithium battery, which can include a lithium-ion or a lithium-polymer battery.
Lithium-polymer batteries often include cells that are packaged in flexible pouches. Such pouches are typically lightweight and inexpensive to manufacture. Moreover, these pouches may be tailored to various cell dimensions, allowing lithium-polymer batteries to be used in space-constrained portable electronic devices such as mobile phones, laptop computers, and/or digital cameras. For example, a lithium-polymer battery cell may achieve a packaging efficiency of 90-95% by enclosing rolled electrodes and electrolyte in an aluminized laminated pouch. Multiple pouches may then be placed side-by-side within the enclosure of a portable electronic device and electrically coupled in series and/or in parallel to form a battery for the portable electronic device. Because the enclosure for the portable electronic device provides physical protection for the pouches, the pouches may not require an additional battery enclosure, thus providing weight and space savings and/or increased battery capacity in the portable electronic device.
Conversely, the lack of a rigid, sealed battery enclosure may increase the susceptibility of lithium-polymer batteries to faults caused by mechanical stress. Such faults may occur during assembly of the batteries, installation of the batteries in portable electronic devices, and/or use of the portable electronic devices. For example, the dropping of an object onto a lightweight portable electronic device may dent the portable electronic device's enclosure, as well as a lithium-polymer battery underneath the enclosure. The dent may deform, weaken, and/or compress the battery's electrodes and/or separator, thus compromising the integrity of the battery and potentially resulting in degraded performance, a short circuit, chemical leakage, and/or another fault in the battery.
Hence, the use of portable electronic devices may be facilitated by mechanisms that improve the resistance of lithium-polymer battery cells to mechanical stress.